Lock stitch sewing machine



July 26, 1949. N. v. CHRISTENSEN ET AL LOCK STITCH SEWING MACHINE 3 SheecsSheet 1 Filed Nov. 5, 1940 -lN| ENTOR$ mrmn/llcizrwiensen & B M80126 SW1,

ATTORNEYS.

3 Shegats-Sheet 2 N. V. CHRISTENSEN ET AL 'LOCK STITCH SEWING MACHINE INVENTORS:

ATTORNEYS.

' Norman TIC/tristensen &

m Na

July 26, 1949.

Filed Nov. 5, 1940 y 6, 1949. N. V. CHRlSTENSE N ETAL 2,477,114

' LOCK STITCH SEWING MACHINE Filed Nov. 5, '1940 3 Sheets-Sheet 3 7'] A TTORNEYS.

Patented July 26, 1949 2S TAT TENT F ICiE fS auer, Berwyn, 111., flassignors to Union Special .MachineCompany, Chicago, 111., a corporation OTTIIIiIIOiS Application November 5, 1940, "Serial No.364;382

'3 Claims. 21

:[fhis invention relates :to :lock stitch sewin machines, and .has reference more particularly to lock stitch sewing .machines of the type in which the rotary hooks :revolve about vertical axes.

Thezchief aim "of ourzinvention is --.to .make it possible to automatically :lubricate the rotary hooks of :such sewing machines by .force action, with avoidance of excess :delivery a of oil by which the needle :and bobbin threads or the work-being sewed in the machine :might become soiled or stained.

In connectionwwith -lubricating .mechanism capable of accomplishing the above, .it is a further air .of our invention to effect the'delivery of oil to the bearing surfaces of the hooks solely by the rotative movement of the hook shafts from a relatively remote :supply source (at "a lower level,

and at the same time to definitely control its pressure :and rate ofiiowin such'a way as to preclude flooding irrespective of the speed of the machine.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings. wherein- Fig. 1 :is a fragmentary view in top plan of the base .or work support 'of iamulttple needle vertical axis hook :lock stitch sewing machine conveniently embodying our invention.

Fig. '2 shows the bottom plan :of the machine.

3 is across section taken as indicated by the arrows .-IHIIZ[ in Figs. 1 and 2.

Figs. 4 and 5 are sectional-views taken as indicated respectively by the arrows IV-IV and VV in Fig. 2, showing important details of individual mounting, which, in accordance with our invention, have been provided for the rotary hooks.

Fig. '6 is a perspective view of one of the rotary hook units of our improved machine.

Fig. i is an exploded view in perspective showing the component parts of one of the rotary hook imits.

Fig. 8 shows the top plan of the rotating component of one of the rotary hook units.

Fig. '9 is a; perspective view of an oil lifting element forming a part of the rotary hook unit.

Figs. 10 and 11 are perspective views respective- 13, of a sealing gasket and a bottom cover plate for one of the rotary hook mountings of the machine; and

Fig. 12 is a view like Fig. 3 showing a modification of our invention.

With more detailed reference first to Figs. 1-11 of these illustrations, the numeral 15 comprehensively designates the base of the machine whereof the top 16 is ofoblon'g corffiguration in plan and serves as the work support. Recessed into the work support [6 adJac-cnt its left hand end and bridging =a-longitudinal slot opening i1 therein, is a throat plate-lfl with'contiguouslyarranged longitudinal gslotsthrough which the toothed sections 1 9=of-a fced dog operata said sections being provided with apertures -20 "for passage through themfrom alcove, of vertically reciprocatory needles 2! tElg. 1) By suitable mechanism, not shown, the needles -2l are vertically reciprocated andalso oscillated laterally in synchronism with the deed dog to assist in the feeding. The end of the shank of the feed dcg appears at 22 in :Fig. -2 and-is secu'redby a screw 23 to a feed bar 24 whereto endwise of -feeding movements as well asup-and down orlift movements are imparted through interposed instrumentalities parthr shown-in Fig. 2,2frorn a rotary shaft 25 which extends longitudinally of the machine below the work support 16 "The-shaft 25 is journalled in sleeve bearings 2'3, 21 fixed in spaced pendant lugs 28:, 28 on the work support it and extends into ahou'sing 30 the right hand end of the machine base containing suitable drive mechanism.

Arranged to respectively cooperate with the needles 21 in stitch formation below the work support in a well known way are'vertical-axis rotary hook units 31, 3'? which are "identical in construction and accessible "from above upon removal of flush cover plates wheredrone is shown at at in Fig. 3 from the pardons or the opening I! in the work support at EDP'O'STEQ sides "6f the throat plate 18. As shown in Figs. 3 and 6, each rotary hook unit includes "a ncuctv cup-like 'r'otating component '35 with a needle thread loop seizing beak 36 and an internal annular bearing groove 31; a hollow non-rotating component 38 with a circumferential file 39 which fits the groove of the rotating com onent, "and 'witha lug projection 40 for engaging a rotation restraining notch (not Shown) in the bdlf'dblh bf jthioat plate 18 at the corresponding "side of the latter; and a thread bobbin 4'! which fits into "said non"- rotating component. The non-rotating "component 38 is held in the assenbry, with capacity for removal when desired or necessary, bye semicircular segmental plate or gib 32 forming a pbrtion of the upper wall of the groove if! in the rotating component 35 and secured in position by a pair of screws 43. In accordance with our invention. the shaft of the hook is inade tubular and preferably formed integrally withthe rotatin was...

component 35 and provided with a bearing shoulder at 46. For the support of the hooks 3| and 32 there are provided individual journals in the form of brackets 41, and 48 which are generally similar in construction and mounted with capacity for adjustment toward or away from each other to suit the spacing of the needles, which spacing may vary considerably depending upon the character of the work for which the machine is to be used. From Fig. 2 it will be noted that the journal brackets 41, 48 have forwardly reaching arms 49, 50 whereof the split ends respectively embrace the bearing sleeves 26, 2'! for the shaft 25 and are secured to said sleeves by binding screws 52. The brackets 41, 48 moreover have laterally-extending portions 53 and 54 with slots at 55 and 56 for passage through them of the shanks of headed screws 51, 58 which engage into aligned rib lugs 59, 60 at the bottom of the work support I6. ,Thus, by loosening the screws 5!, 52, 5'! and 5,8, the journal brackets 41 and 48 may be shifted'until the proper setting for the rotary hooks is obtained, and thereafter fixed in their new positions by; rte-tightening said screws. The journal brackets 41, 48 are further characterized by having upright portions 6! and 62 with vertically-spaced lateral upper and lower bearing lugs 53 and 64 which are apertured as at 65 and 55m receive bearing bushings 61, 68 for the shafts 45 of the respective hook rotating components as instanced in Fig. 3. Fast on the hook shafts 45 in the intervals between the bearing lugs 63, 54 on the brackets 41, 48 are spiral gear pinions 10, H which mesh respectively with driving pinions I2, 13 on the horizontal shaft 25 hereinbefore referred to, the latter pinion being secured by set screws so that they may be shifted along the shaft 25 when the position of the brackets is adjusted as and for the purpose already explained. The ratio of the gearing just described is such in the present instance as to determine two rotationsof the hooks for each reciprocation of the needles. v At the rear, the upright portions GI, 62 of the brackets 41, 48 have vertical cavities 15, 16 respectively, which, together with the apertures in the lower bearing lugs 63, 64 are closed by removable screw-secured bottom cover platesv .11 and 18 (Figs. 4 and 5) with interposition of sealing gaskets l9 and 80. As instanced in Fig. 3, in each bracket the lower journal bushing 68 terminates short of the bottom of the bore 66 to provide a clear space at 8| which latter is in communication, by way of a horizontal connecting passage 82, with the cavity 15. In practice, each of the cavities 15, I6 is utilized as a well which is kept filled with lubricating oil to the level conventionally indicated in Fig. 3, and each has a vent 84 at the top to prevent it from becoming air bound. Disposed within the hollow of each hook shaft 45 is a core element in the form of a cylindric pin 85 of smaller diameter, with a lengthwise-extending spiral groove 86, and with a flattened bottom end 81 which latter fits, into a similarly shaped recess 88 in the corresponding cover plate H to keep said. pin from rotating with said hook shaft. The upper end of the axial cavity in each hook shaft 45 is closed by an upwardly-concaved cap plate 89 whereof the circumferential margin is welded or otherwise permanently secured to the bottom of the hollow in the rotating component 35 of the hook, with resultant formation of a cavity 90 from which a duct 9Ileads laterally to the groove 31 in said hook component. Also, as instanced in Fig. 3, a porous plug 92 is inserted into the top of each hook shaft 45 somewhat above the upper end of the core pin 85. For convenience of replenishing the oil from time to time, I have provided tubes 93, 94 whereof the filling ends are capped as at 95, 96 and accessible from above through the opening I! in the work support It. As shown in Fig. 4, the tube 93 has a horizontal branch 93a which extends laterally into the oil well 15 of the bracket 41; while from Fig. 5 it will be observed that the tube 94 leads straight downward and connects with a horizontal bore 91 in the bracket 48 which bore, in turn leads to the oil well 16, each tube having in its upper end, a removable insert filter screen such as shown at 98 in Fig. 4.

As a consequence of the afore-described construction, it will be apparent that, during the operation of the machine, by coaction between the internal surfaces of the hook shafts 45 and the spiral grooves in the stationary core pins 85, oil will be constantly lifted from the supply in the wells 15, 16 to the spaces above said pins, wherefrom it will percolate through the porous plugs into the cavities in the bases of the rotating components 35 of the hooks and finally flow, by way of the ducts 9| and under the further influence of centrifugal action, to the annular hearing grooves 31 in said components. Due to the clearances around the core pins 85 and by virtue of the checking influence of the porous plugs 92, the rate of oil flow and its pressure will be definitely controlled to prevent delivery of excess oil to the hooks, so that soiling or staining either of the sewing threads or'the work operated upon will be efiectively precluded irrespective of the speed of the machine. A further advantage of our invention is that the hooks are lubricated only while the machine is running. During the idle periods, the oil within the hollows of the hook shafts 45 will obviously drain downward to a level common with that in the wells 15 and I6.

In the modification shown in Fig. 12, the core pin 85a is of plain cylindric configuration and the oil lifting groove 86a formed internally of the hollow of the hook shaft 45. In all other respects, the construction of the modification is identical with that of the first described embodiment of our invention. Accordingly, in order to preclude repetitive description, all the other elements shown in the modification and not specifically referred to but having their counterparts in the first described embodiment, are identified by the reference numerals previously employed.

It is of course to be understood that our invention is not necessarily limited to needle feed lock stitch machines with multiple needles such as herein illustrated by way of example, since, as will be readily understood by those skilled in the sewing art, it can be incorporated with attainment of advantages equal in all respects to those hereinbefore pointed out, in single or multiple needle lock stitch machines in which the needles are confined solely to endwise reciprooation.

In any case, our invention provides for the automatic lubrication of the hooks with oil especially suited to them and taken from sources which are isolated from those provided for the lubrication of other parts of the machine mechanisms.

Having thus described our invention we claim:

1. In a lock stitch sewing machine, a vertically reciprocating needle; a vertical axis rotary hook to cooperate with the needle in stitch formation, said hook having a rotating component including a pendant shaft, and a non-rotating component with a bearing surface in engagement with a corresponding bearing surface on the rotating component; a bracket supporting a bearing for said shaft and provided with an oil supply reservoir; means spaced from said bearing coacting with the shaft during its rotation to lift oil from the reservoir for lubrication of the contacting bearing surfaces of the rotating and non-rotating components aforesaid, said pendant shaft being tubular and closed at its upper end; a duct extending laterally from the upper end of the shaft hollow into the bearing surfaces aforesaid; said means spaced from said bearing and cooperating with the shaft to lift the oil being in the form of a cylindric core element having an external spiral groove, said element extending upward into the shaft hollow from beneath and terminating below the top of the shaft hollow; and a porous plug disposed in the top of the shaft hollow above the core element for controlling the amount of oil delivered to the hook.

2. In a lock stitch sewing machine, a vertically reciprocating needle; a vertical axis rotary hook to cooperate with the needle in stitch formation, said hook having a rotating component including a pendant shaft, and a non-rotating component with a bearing surface in engagement with a corresponding bearing surface on the rotating component; a bracket supporting a bearing for said shaft and provided with an oil supply reservoir; means spaced from said bearing coacting with the shaft during its rotation to lift oil from the reservoir for lubrication of the contacting bearing surfaces of the rotating and non-rotating components aforesaid, said pendant shaft being tubular and closed at its upper end; a duct extending laterally from the upper end of the shaft hollow into the bearing surfaces aforesaid; said means spaced from said bearing and cooperating with the shaft to lift the oil being in the form of a cylindric core element with an external spiral groove, said core element being of smaller diameter than the shaft hollow with provision of a slight clearance all around, and extending upward into the shaft from beneath and terminating below the top of the shaft hollow, and a porous plug disposed at the top of the shaft hollow above the core element for controlling the amount of oil delivered to the hook.

3. In a lock stitch sewing machine, a vertically reciprocating needle; a vertical axis rotary hook to cooperate with the needle in stitch formation, said hook having a rotating component including a pendant shaft, and a non-rotating component with a bearing surface in engagement with a corresponding bearing surface on the rotating component; a bracket supporting a bearing for said shaft and provided with an oil reservoir; means spaced from said bearing coacting with the shaft during its rotation to lift oil from the reservoir for lubrication of the contacting bearing surfaces of the rotating and non-rotating components aforesaid, said pendant shaft being tubular and said means spaced from said bearing and cooperating with the shaft to lift the oil being in the form of a cylindric core element which extends upward into the shaft hollow from beneath and has a lengthwise spiral groove; said bracket being formed to one side of the shaft bearing with a vertical oil cavity or well which communicates, by way of a lateral connecting passage, with the bottom of the bore of the shaft bearing, said cavity and bore being open at the bottom; a removable cover plate arranged to close the open bottoms of the shaft bore and the cavity; and the lower end of the core element being squared to fit into a similarly configured recess in the cover plate.

NORMAN V. CHRISTENSEN. GEORGE SAUER.

REFERENCES CITED The following references are of record in the file of this patent:

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